Heck Reactions with Ultralow Concentration of Transition Metals under Microwave Irradiation

Abstract

The Heck coupling reactions of aryl halides and olefins were performed under the microwave assistance. Inte- restingly, the ultralow concentration of transition metals (in ppb) coming from the reactants could catalyze the Heck coupling reactions under microwave irradiation, without addition of any catalysts, ligands and phase- transfer agents. The influences of bases, solvents and temperature were discussed, and the reaction rate was en- hanced largely in the mixed solvents of NMP and water due to the solubility of base in water.